Working on 282 Gantry Crane

It'a probably a combination. About 30 years ago I rewired the magnet to work off a separate transformer(I use a small 1015) so I can apply/adjust only as much current as the magnet needs, and the crane operation does not affect the magnet performance.

I have a problem with the magnet too. It just stoped working and the light in the cab went out also. I haven't found any broken wires??????? The other controls work fine.

gene maag posted:

I have a problem with the magnet too. It just stoped working and the light in the cab went out also...

The finger/wiper that rides on the center post inside the cab may have slipped off.

I rebuilt a 182 crane several months ago and experienced momentary power interruptions to the magnet as you describe. The problem was as you speculated brief ground interruptions due to cab vibration. On the 182 the ground side of the circuit is transmitted through the outside of the center shaft. There was no bearing or bushing for this shaft. There was just a hole in the base which had worn unevenly and did not stabilize the shaft causing a circuit interruption when the cab vibrated. Rather than turn a bearing and re-drill the base I stabilized the cab by stacking 1 inch washers around the shaft so that the cab actually rides on the washers providing firm ground contact. The washers are greased with conducting grease 

ADCX Rob posted:

It'a probably a combination. About 30 years ago I rewired the magnet to work off a separate transformer(I use a small 1015) so I can apply/adjust only as much current as the magnet needs, and the crane operation does not affect the magnet performance.

Thanks, Rob,

Were you able to connect the transformer so the regular controller can still be used? 

Yes, I made the connection at the controller with the small transformer in phase with the 1033 that powers the rest of the crane.

The one change I made was to disable the magnet lever so the transformer lever takes over for magnet on/off, but this was only because the controller is on the panel in a position that it was too easy to lean on the lever and turn it on by accident and this was happening a lot.

Thanks all for the advice. Rob's suggestion did the trick!! I opened the controller, un-soldered the wire (#4) that the magnet lever powers, re-soldered the wire to another piece of wire which I ran out of the opening in the back of the controller (with the other wires), connected the new magnet wire to a small (25 watt) transformer, and connected the other transformer lug to the layout ground (properly phased). The magnet no longer lets go of its load when the solenoid is engaged!

The only remaining, minor, issue is that the boom tends to rotate a bit while I'm trying to run the magnet up or down. The solenoid clutch does not seem to completely disengage the rotation mechanism.

My 282 does that too.  Run the magnet very briefly in the opposite direction when stopped (up, if going down, down if going up) and you should hear the solenoid disengage.  Then you can lift/lower your load without the crane rotating.  Good luck!